Abstract
Abstract. For more than 2 decades, satellite observations from instruments such as GOME, SCIAMACHY, GOME-2, and OMI have been used for the monitoring of bromine monoxide (BrO) distributions on global and regional scales. In October 2017, the TROPOspheric Monitoring Instrument (TROPOMI) was launched on board the Copernicus Sentinel-5 Precursor platform with the goal of continuous daily global trace gas observations with unprecedented spatial resolution. In this study, sensitivity tests were performed to find an optimal wavelength range for TROPOMI BrO retrievals under various measurement conditions. From these sensitivity tests, a wavelength range for TROPOMI BrO retrievals was determined and global data for April 2018 as well as for several case studies were retrieved. Comparison with GOME-2 and OMI BrO retrievals shows good consistency and low scatter of the columns. The examples of individual TROPOMI overpasses show that due to the better signal-to-noise ratio and finer spatial resolution of 3.5×7 km2, TROPOMI BrO retrievals provide good data quality with low fitting errors and unique information on small-scale variabilities in various BrO source regions such as Arctic sea ice, salt marshes, and volcanoes.
Highlights
Bromine monoxide (BrO) plays an important role in atmospheric chemistry
The data in rows 42 to 45 were ignored because it was apparent from the BrO slant column density (SCD) that they were affected by the row anomaly they were not marked as bad pixels
This might reflect real BrO column increases but could at least partially be related to the use of geometric air mass factors (AMFs), which do not consider the effects of surface albedo and clouds
Summary
Bromine monoxide (BrO) plays an important role in atmospheric chemistry. In the lower stratosphere, it is involved in chain reactions that deplete ozone (Wennberg et al, 1994), and bromine in the troposphere changes the oxidizing capacity through the destruction of ozone, which is a primary precursor of atmospheric oxidation in the troposphere (von Glasow et al, 2004). Ground-based measurements with localized spatial coverage are limited in observing large-scale BrO explosion events and long-range transport of BrO plumes. This can be overcome by satellite measurements having extensive spatial coverage albeit at coarse spatial resolution and limited temporal sampling. An offset value for normalization of the differential BrO SCDs is determined as the mode of the Gaussian distribution of differences between the differential SCDs in the reference sector and the normalized SCDs estimated by multiplying the background VCD and a geometric air mass factor defined as AMFgeo = 1 cos(SZA) + 1 cos(VZA). This offset value is modified for each row depending on the viewing zenith angle (VZA) to account for variations in the BrO air mass factor. The normalized SCDs are calculated by subtracting the VZA-dependent offset values from the measured SCDs
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
